Process of producing multicolor pictures.



No.67|,'|s5. Patented Apr. `2, |901.

A L-. KUHN.

PRUCESS 0F PBODUCING MULTICOLUB PICTURES.

. (Application mea van. 24, 189s.) (No Modei.)

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LUDWIG Kl-IN, OF NUREMBERG, GERMANY, ASSIGNOR TO ERNST NISTER, OF SAME PLACE.

PROCESS OF PRODUCING MULTICOLOR PICTURES.

SPECIFICATION formingpart of Letters Patent o. 671,165, 'dated April 2, 1901.

Application tied-January 24, 1896. Serial No. 576,693. (No specimens.)

.To a/ZZ whom, t may 00u/cern.'

Be it known that I, LUDWIG KHN, a subject of the King of Bavaria, residing at Nuremberg, in the Kingdom of Bavaria, Germany, have invented a new and useful Process of Producing Pictures of Many Colors, of which the following is a specification.

In making chromolithographs as generally practiced at the present time there are re- Io quired many printing-blocks, each for a different tint or color, from which impressions are made one over the other upon the sheet on which the picture is to be made. The number of blocks required varies with the character of the picture to be reproduced and may range from ten to forty or more. This large number of blocks is rendered necessary because the eye cannot directly resolve the colors of the original into the primary colors,

2o (red, blue, and yellow,) so as to be able to estimate their proportions in the compound colors of the original. If this were possible, the color-printer would have to provide and print practically from only three blocks, one

for each of the primary colors. Already attemptstoeect this have been made-for example, by the process described by Hosch in the German Patent No. 17,410 and also described in the United States Patent to Hosch,

3o No. 287,938.

The present invention relates to a process which has for its object the reduction in number of the printing-blocks from which the chromo is actually printed to three, one for each of the primary colors.

In order to carry out the process, it is necessary to first make the number of blocks that would be required according to the ordinary method of printing, and by means of 4o this number of blocks to prepare three blocks, one for each primary color, from which the chromo will actually be printed. For the sake of brevity and distinction the blocks first prepared Will be termed original blocks and the three blocks subsequently prepared will be termed the printing-blocks.

The original blocks are prepared in the usual manner, and eachis for a tint or color dierent from the others, and each carries a 5o printing-surface representing so much of the vto print in the necessary colors.

original design as is necessary to print in its color. Now each tint or color represented by these blocks may be resolved into its pri mary colors and also the particular shade of each primary color necessary to produce it either by the eye of the artist or by the aid of a suitable color-scale-sucl1, for instance, as described in United States Patent to Hosch, No. 287,938. This having been ascertained, three sheets are provided, each to represent a primary color. The original blocks are then put into a press separately and an impression taken from each on one or more of the sheets, according to the primary color or colors into which the color of such block has been resolved. These impressions are printed not in the special colors, but in a neutral tint, such as gray or brown. Impressions are taken from eachof the original blocks successively upon these sheets, such impressions being one over the other. After all the impressions necessary upon each sheet have been made each sheet Will be a combinationsheet printed in a neutral tint representing all of one of the primary colors that would have been printed by all the original blocks in producing the chromo. From these sheets are produced by any suitable reproduction process-easier example, photography-three printing-blocks which are used to print with the respective primary colors one over the other, and thus produce the chromo by making only three impressions on the sheet instead of as many impressions as there were original blocks.

As an illustration of carrying out my process reference may be had to the accompanying drawings, in which- Figure l is a diagram which may represent a picture to be copied and which would re quire under the usual process sixteen blocks Fig. 2 is a diagram which may represent the three sheets produced by printing from the original blocks. Fig. 3 is a similar diagram which may represent the printing-blocks made by the reproduction thereon of the sheets in Fig. 2. Fig. 4 is a diagram which may represent the chromo produced by the impressions made one upon the other by the printing-blocks in IOO Fig. 3. Fig. 5 shows an arrangement of lines to indicate the primary colors-yellow, red, and blue. Y

It will be seen that I have arbitrarily indiv cated yellow by a series of vertical lines, red

by a series of horizontal lines7 and blue bya of the blocks only are shaded, and these may' be assumed to represent -a flesh tint, the first yellow, and the first gray in blocks 4l, 2, and 3, respectively, in Figl. By the terms first yellow and first gray I mean the-lightest shade of the respective colors presen-t inthe picture. The next darker shade would be termed second yellow or second gray, as the case `might be, and so'on according to the number of different shades of the same color present in thepCture. Now on res0lv ing fiesh tint into `its primary colors it is fou-nd to contain yellow and red, and therefore it is arbitrarily represented by yer-tical and horizontal lines crossing `each other aft rghtangles. Now assuming an original block to be made for printing lall the flesh tint in the picture, an impression would be made from such block on sheets A and AB, vvrepresenting yellow and red, respectively, in a neutral color-as, for instance, gray-'and while vthe-outline ofthese impressions would bethe same on both sheets Vtheir degreeof shade or depth of color might rbe varied according as the yellowor red imight have to predominate. The flesh tint has a'slight tendency'toward yellow, and -as ltheredis asomewhat more penetrating color'it wouldibe-necessarytoprintsheet A a'shade darker than sheet B.

A skilledcolor artist Vor .printer is able to determine by sight onlythe primary'colors necessary to produce any tint or color #and also-the particular. shade of'suchprirnary colors and is'also able to select the'corresponding shade of neutral color; but 'for the purposeof readilydetermining the shadefof-the neutral color to be used the loperator may have prepared four scales', one for each of the primary colors (yellow, red, and blue)vand one for the neutral color. Each of these 4scales may `have on it twenty or more different shades of its color, gradaullyiincreasing in depth from the lightestto the darkest, and which may-be'numbered, beginningwiththe lightest shade of such color and vending with the darkest. Experience has proven that for practical purposestwenty different shades of one colorare all thatare'essentiallynecessary in color-printing and that `when fmore are used the successive shades vcannot be csr/Lies readily distinguished by the naked eye. Assuming, therefore, that fourscales have been preparedone for yellow, one for red, one for blue, and one for the neutral color-and that each scale has on it twenty different shades of its color, gradually increasing in depth from thelightest to the darkest and numbered Yconsecutively from l t0 20, the various Atint contains yellow and red, with a slight tendency toward yellow, the artist vis able to determine 'whichcf vthe particular shades of yellow and :red contained on the scales ol these colors is necessary-to.produce the flesh tint. `lilzrperience shows that shade No. 4 of yellow andshade No. 3'of red (in the scale of twenty dierent shades) will produce the ordinary desh tint, and lin printing 4on the combination-sheets shade No. l of gray will be fused onsheet A and shade No. 3 of gray on sheet 1B.

r`Ilhe'first-yellow in block 2isa primary color, and consequentlyanfirnpressionfrom the original blockdesigned to print all :the `first yellow i:n-the ipicture would have to be made in neutral-coloron sheetAlonly. As the first yellow is somewhat 1darker than :the yellow entering i-nto the flesh tint, the neutral color should be a shade lor two darker than that used for fiesh tint.

The first gray is resolved :into yellow, red, and fblue, fand thereforean limpression ymust be made lfrom theoriginalblockfor this color oneach sheet A, B,"and C, the -latter representingfblue. Each impression should bein quite alight shade of' neutrallcolor--that on sheet C beingfthedarkest-say shadeNo. 3 and that on sheet iB the lightestsay shade No. l-while thaton sheetA should-be intermediatesay shade No. 2.

Thedotted lines in the rblocks Yl, 2 land 3 of fsheet A represent 4different ldegrees of shade, lthose in block 2 lbeing the darkest, thosefin block rlnext, and lthose in block 3 next. The same inirespectto-sheet B, where block lds darker than block3.

The foregoingiis' sufficient to-give a'clear idea-of thecourse ofiprocedure in forming the sheets A, B,-andC,.and after all'theroriginal block-shave beenusedthe sheets will frespectively represent in aneutral'color every part ofthe `picture .to which it will be necessary to apply fthe respective `primaryfcolors and alsothe shadelor depth of*l such color. These sheets are next reproduced upon 'threeprinting blocksI orstones-by an yV ofthe well-k nown processesand willbe usedto print in yellow, red,fand blue, respectively. The .yellow .will be.printed-first,the:red next, andlfinally the blue. The colors employed zfor the final IOO IIO

printing must be the pure tints of yellow, red, and blue, such as are ordinarily used in three-color printing.

By the term block in the foregoing specification I desire to be understood as meaning` any kind of stone, plate, or block ordinarily employed in this art. Also by the Word chromo I mean any muticolored picture or design.

Having described my invention, I claim-- 1. The herein-described process of prod ucing blocks for printing chromos, Which consists in first preparing a number of original blocks, one for each color necessary to be used in the chromo, then resolving such colors into their primary colors, then forming combination-sheets, one for each primary color, by making impressions thereon from said blocks one over the other, and then reproducing said combination-sheets on blocks7 substantially as set forth.

2. The herein-described process of producing chromos, which consists in preparing for each color to be used in the chromo a block capable of printing all necessary parts in such color, resolving said colors into their primary colors, then preparing combination-sheets, one for each primary color by making impressions thereon in a neutral color from said blocks, one over the other, then reproducing said combination-sheets on blocks, and then printing with primary colors from the latter blocks, substantially as set forth.

3. The herein-described process of producing chromos,`Which consists in first preparing a plurality of original blocks, one for each color necessary to be used in the production of the chromo and each capable of printing its color on all necessary parts of the sheet on which the chromo is produced, next resolving the color of each block into its primary colors, then making an impression in a neutral color from each block on as many separate sheets as there are primary colors in the color it was designed to print, the impressions from said blocks being made on the same sheet for each primary color one over the other, whereby three combination-sheets are made each representing all of a primary color that Would be represented by all the blocks, next reproducing said combinationsheets on printing-blocks, and then printing from said blocks in the primary colors, the impression from said blocks being one over the other, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

LUDWIG KUHN.

Witnesses:

CARL RoEsoHEL, OSCAR BooK. 

